2007-12-13 Golovanevsky Olga <olga@il.ibm.com>

	* doc/invoke.texi (Optimiza Options): Document new -fipa-struct-reorg
	option and struct-reorg-cold-struct-ratio parameter.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@130890 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 00bf7c6..952bb9a 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2007-12-13  Golovanevsky Olga  <olga@il.ibm.com>
+
+       * doc/invoke.texi (Optimiza Options): Document new -fipa-struct-reorg
+       option and struct-reorg-cold-struct-ratio parameter.
+       
 2007-12-13  Torbjorn Granlund  <tege@swox.com>
 
        * config/i386/i386.c (ix86_rtx_costs) [MULT]: Check op0 for

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 3376420..e8431da 100644 (file)
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -329,7 +329,7 @@ Objective-C and Objective-C++ Dialects}.
 -fgcse-sm -fif-conversion -fif-conversion2 -finline-functions @gol
 -finline-functions-called-once -finline-limit=@var{n} @gol
 -finline-small-functions -fipa-cp -fipa-marix-reorg -fipa-pta @gol 
--fipa-pure-const -fipa-reference @gol
+-fipa-pure-const -fipa-reference -fipa-struct-reorg @gol
 -fipa-type-escape -fivopts -fkeep-inline-functions -fkeep-static-consts @gol
 -fmerge-all-constants -fmerge-constants -fmodulo-sched @gol
 -fmodulo-sched-allow-regmoves -fmove-loop-invariants -fmudflap @gol
@@ -5707,6 +5707,20 @@ Discover which static variables do not escape cannot escape the
 compilation unit.
 Enabled by default at @option{-O} and higher.
 
+@item -fipa-struct-reorg
+@opindex fipa-struct-reorg
+Perform structure reorganization optimization, that change C-like structures 
+layout in order to better utilize spatial locality.  This transformation is 
+affective for programs containing arrays of structures.  Available in two 
+compilation modes: profile-based (enabled with @option{-fprofile-generate})
+or static (which uses built-in heuristics).  Require @option{-fipa-type-escape}
+to provide the safety of this transformation.  It works only in whole program
+mode, so it requires @option{-fwhole-program} and @option{-combine} to be
+enabled.  Structures considered @samp{cold} by this transformation are not
+affected (see @option{--param struct-reorg-cold-struct-ratio=@var{value}}).
+
+With this flag, the program debug info reflects a new structure layout.
+
 @item -fipa-pta
 @opindex fipa-pta
 Perform interprocedural pointer analysis.
@@ -6643,6 +6657,15 @@ of bytes in instantiated fields to the number of bytes in the complete
 structure exceeds this parameter, then block copies are not used.  The
 default is 75.
 
+@item struct-reorg-cold-struct-ratio
+The threshold ratio (as a percentage) between a structure frequency
+and the frequency of the hottest structure in the program.  This parameter
+is used by struct-reorg optimization enabled by @option{-fipa-struct-reorg}.
+We say that if the ratio of a structure frequency, calculated by profiling, 
+to the hottest structure frequency in the program is less than this 
+parameter, then structure reorganization is not applied to this structure.
+The default is 10.
+
 @item max-crossjump-edges
 The maximum number of incoming edges to consider for crossjumping.
 The algorithm used by @option{-fcrossjumping} is @math{O(N^2)} in